Circuit interrupter



July 6, 1943. I B. P. BAKER 2,323,642

CIRCUIT INTERRUP'IER Filed March 31, 1942 2 Sheets-Sheet 1 WITNESSES: INVENTOR z zzmam Patented July 6, 1943 UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER Benjamin F. Baker, Turtle Creek, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application March 31, 1942, Serial No. 437,001

24 Claims.

are set forth and broadly claimed in my copend-v ing application Serial No. 435,380, filed March 19, 1942, now Patent 2,303,524, issued December 1, 1942, entitled Circuit interrupters, and assigned to the assignee of this application.

It is well known that two conductors carrying current in opposite directions and disposed adjacent one another will tend to repel each other. I use this well known principle in controlling the position of the arc in circuit breakers of the foregoing type as a function of the instantaneous arcing current. Thus during relatively high instantaneous values of current I move the arc to one side, or directly away, from the port, adjacent to which it is drawn, to permit a comparatively free venting of the arc extinguishing fluid under pressure through said port and out of the arcing chamber. During relatively low instantaneous values of current at a time suit able for arc interruption I permit the arc to re-' turn to the place where it was initially drawn, that is, directly in front of the port. Here it is blasted by a substantially transverse flow of arc extinguishing fluid to cause its extinction.

I control the position of the arc and the movement thereof with respect to said vent by the disturbance of the magnetic field surrounding said arc. I may do this in a number of ways. First, a series conductor in the electrical circuit passing through the interrupter may be disposed near to the point of drawing the arc, and the interaction of the magnetic fields set up surrounding said are and said series conductor may be such as to force the are away from the vent in the arc extinguishing chamber during high instantaneous values of arcing current, the efiect of low values of instantaneous current being to diminish the strength of the magnetic fields surrounding said arc and said series conductor and hence to result in the are being permitted to return to the position where it was initially drawn.

I may also draw two series arcs adjacent one I cent to which it is drawn.

another, the interaction of the magnetic fields surrounding said series arcs being such to move each of said series arcs away from the vent in a Wall of the arc extinguishing chamber adja- Or I ma draw a single arc and dispose adjacent thereto a sheet of magnetic material, the effect of the magnetic material being to attract the arc and hence to displace the position of the same. Instead of providing a single sheet of magnetic material I may provide a piece of magnetic material substantially surrounding the areing chamber and moving the arc to a new posi-.

tion directly away from the vent adjacent to which it is drawn.

I may also use a series coil in the interrupter circuit so disposed that the magnetic field resulting therefrom will be such as to move the arc laterally to one side of, or directly away from, a vent provided in a wall of the arc extinguishing chamber. Or I may use an arc extinguishing chamber in which two series arcs are drawn, and one or more series conductors disposed adjacent.

to one of said arcs to efiect the movement of the same.

In all of the previously mentioned embodiments of my invention it will be apparent that maximum interaction of the magnetic fields will take place during the peak of the current wave,'

the efiect of low instantaneous values of current being such as to diminish the strength of the magnetic fields set up about the arcs or conductors, and hence to permit the arc to be moved.

back to the position where it was initially drawn.

In many of the interrupters now on the market the method of arc extinction is to draw an are adjacent a vent disposed in a wall of a suitable arc extinguishing chamber within which is disposed a suitable arc extinguishing fluid. When circuit interruption is desired, pressure is produced by some suitable means within the arc extinguishing chamber and an arc is drawn adjacent a vent or aperture in the wall of said chamber to receive a cross blast of arc extinguishing fluid which traverses the arc stream substantially perpendicular thereof and passes through the vent or aperture out of the chamber.

This method of arc extinction produces high arc stream and substantially perpendicularly thereto regardless of the value of instantaneous arcing current, the arc voltage increases unnecessarily and the amount of gas generation is high. The internal pressure within the arcing chamher is correspondingly high,

In the method of arc extinction which I use in my invention I provide a cross-blast of arc extinguishing fluid through the arc stream at or near a current zero in the current wave. During relatively high values of instantaneous arcing current I move the arc stream laterally to one side of the vent or aperture in the casing of the arc chamber, or I may move the arc directly away from the vent or aperture to permit a relatively free flowing of arc extinguishing fluid out through the vent during high instantaneous values of arcing current without disturbing the continuity of the arc stream, and consequently producing little increase in arc voltage and little generation of gas. When, however, the instantaneous value of arcing current is relatively low, the arc is permitted to move back to the position where it was initially drawn or near the vent and splitters which may form the interrupting element and in this position it receives the full effect of a cross-blast of arc extinguishing fluid through the arc stream and out through the vent from the arcing chamber.

In this latter method of arc extinction by disturbing the continuity of the arc as little as possible during high instantaneous values of arcing current interrupting performance is improved by lower arc voltage and a lower amount of gas generation. When the instantaneous value of arcing current falls to a relatively low value, and at this time when the conditions are ripe for are extinction, the arc stream is moved directly in front of the vent at the position where it was initially drawn and are extinction is effected at or near a current zero.

It is a general object of the present invention to provide a circuit interrupter which operates in accordance with the principles outlined in the aforementioned method of arc extinction.

It is also an object of the present invention to provide an interrupter in which the arc to be interrupted is moved in accordance with the value of the instantaneous arcing current.

It is also an object of my invention to provide an interrupter in which a varying field of flow of arc extinguishing fluid is provided, and in which means are provided to move the arc to be interrupted during high instantaneous values of arcing current from a point of high velocity of flow to a point of low velocity of flow, and upon the return of low instantaneous values of arcing current to permit a return of the arc to a position of high velocity of fluid flow.

It is also an object of the present invention to provide a circuit interrupter in which a flow of arc extinguishing fluid is produced and to vary said flow with respect to an arc to be interrupted as a function of the instantaneous value of arcing current.

Another object is to provide a circuit interrupter with a substantially closed arcing chamber, said chamber containing a vent across which an arc to be interrupted is drawn, means for producing a flow of fluid through said vent, and means for moving said arc during high instantaneous values of arcing current to one side of said vent where the flow of fluid is relatively small.

Another object is to provide a circuit interrupter in which a varying field of flow of are extinguishing fluid is produced and to move the arc to be interrupted during high instantaneous values of arcing current to a point of low fluid velocity by placing magnetic material adjacent the arc path.

A specific object of the present invention is to utilize the magnetic field set up by either a series are or one or more series conductors in the interrupting circuit to effect this movement of the arc with respect to the vent adjacent to which it is drawn.

Another object is to provide an interrupter in which one or more series arcs are drawn, one of said series arcs being utilized to provide the necessary pressure within the arcing chamber and the other of said series arcs being moved by any of the means mentioned above.

Another object of the present invention is to disturb the magnetic field surrounding an arc and consequently to displace the position of the arc stream substantially only durin relatively high instantaneous values of arcing current.

Many more objects of the present invention will be readily ascertainable by a reading of the following description concerning several embodiments of the present invention.

Figure 1 is an elevational view, partially in section, of a circuit interrupter constructed in accordance with the principles of my invention and shown in the partly open circuit position;

Fig. 2 is a transverse cross-sectional View of the interrupter shown in Fig. 1 taken substantially on the lines IIII of Fig. l and looking in the direction of the arrows;

Fig. 3 is an elevational view of a modified type of circuit interrupter, partially in section, and constructed in accordance with my invention;

Fig. 4 is an elevational View of the circuit interrupter shown in Fig. 3 taken substantially at right angles to the circuit interrupter shown in Fig. 3;

Fig. 5 is a transverse cross-sectional view of a modified type of circuit interrupter illustrated in Fig. 7, taken along the line V-V of Fig. 7 looking in the direction of the arrows;

Fig. 6 is an elevational view, partially in section, of the modified type of circuit interrupter shown in Fig. 7 and taken at substantially right angles to the interrupter shown in Fig. 7;

Fig. 7 is an elevational view, partially in section, of a modified type of circuit interrupter;

Fig. 8 is a transverse cross-sectional View of a modified type of circuit interrupter shown in Fig. 9 taken along the line VIII--VIII of Fig. 9 and looking in the direction of the arrows;

Figv 9 is an elevational view, partially in section, of a modified type of circuit interrupter;

Fig. 10 is a transverse cross-sectional view of the modified form of interrupter shown in Fig. 11, taken substantially on the line X-X of Fig. 11 and looking in the direction or" the arrows;

Fig. 11 is a side elevational view, partially in section, of a modified form of interrupter;

Fig. 12 is a transverse cross-sectional view of the modified form of circuit interrupter illustrated in Fig. 13, taken substantially along the line XII-XII of Fig. 13 and looking in the direction of the arrows;

Fig. 13 is an elevational view, partially in section, of still another embodiment of the present invention;

Fig. 14 is a side elevational view taken at right angles to the view in Fig. 13; and

Fig. 15 is a side elevational view, partially in 2,'s'2s,o4'2 I section, of still another embodiment of the present invention.

Referring particularly to Fig. 1, the reference numeral I designates an insulating casing provided with two flared apertures or vents 2, 3 bored in the wall of said casing. A relatively movable contact structure provided in the interior of said casing I comprises two stationary contacts 5, 6 and a conducting bridging bar 1, at the ends of which are the two movable contacts 8, 9. The bridging bar 1 is actuated by an insulating operating rod II, which is guided through an extension I3 of the wall of the easing I. A bell crank I5 pivoted at I1 to the wall of the casing I, is pivotally connected at one end I9 to a piston-shaped operating rod 2|, which projects through the top 23 of the casing I. The other end of the bell crank I5 contains a slot 25 which cooperates with a pin 21 rigidly secured to the operating rod II.

It will be apparent that downward motion of the piston-shaped operating rod 2I will cause a clockwise rotation of the bell crank I5 about the pivot point I1 to actuate the insulating operating rod II to the left, as viewed in Fig. 1, to separate the respective movable contacts 8, 9 from the stationary contacts 6, 5. It is also apparent that the electrical circuit through the interrupter consists of the external line terminal 29, the upper stationary contact 5, the upper movable contact 9, the conducting bridging bar 1, the lower movable contact 8, the lower stationary contact 6 and the lower external line terminal 3|.

The insulating casing I is immersed in a suitable arc extinguishing liquid, such as oil. It will be observed that when the insulating operating rod II is actuated to the left, as viewed in Fig. 1, two series arcs will be drawn in the interior of the casing I between the respective stationary contacts 5, 6 and the movable contacts 9, 8. These arcs will react upon the arc extinguishing liquid contained within the casing I to create pressure therein. At the same time that the series arcs are being drawn, piston-shaped operating rod 2|, actuated by external means not shown, moving downward into the insulating casing I will displace arc extinguishing liquid to further increase the pressure of the liquid contained therein.

Assuming that the instantaneous current passing through the interrupter is in a direction indicated by the arrows 33, it will be apparent that the series arcs, the initial positions of which are indicated by the dotted lines 35, 36 have their own magnetic fields surrounding them, which fields interact with the magnetic fields set up around horizontal portions 31, 39 of the conducting bridging bar 1. The interaction of the respective magnetic fields set up about the arcs 35, 36, and about the horizontal portions 31, 38 of the conducting bridging bar 1 will be such as to force the arcs 35, 36 to the respective positions indicated by the dotted lines 39, 49.

Consequently, during high instantaneous valuesof current passing through the interrupter the arcs 35, 36 will be forced to respective positions 39, 49 to one side of the vents 2, 3. The fluid under pressure within the casing I may then freely pass out through the vents 2, 3 carrying with it the excess ionized gas surrounding the arc stream without substantially interfering with the displaced arcs 39, 49. When, however, the instantaneous value of current through the interrupter'falls to a relatively low value, the maghorizontal portions 31, 38 of the conducting bridging bar 1 will diminish. The result of the diminution of the magnetic field strength will be to permit the arcs 39, 49 to return to their former positions 35, 36, at which positions the arcs will be subjected to a strong cross-blast of fluid transversely to the arc streams and out of the insulating casing I through the vents 2, 3.

Thus I have provided an interrupter in which two series arcs are drawn within an insulating casing I. During high instantaneous values of arcing current the arcs are moved laterally to one side of the vents 2, 3 to permit a relatively free flowing of the fluid under pressure out of the casing I through the vents 2, 3. The pressure within the casing I is caused by the arcs themselves, and also by the downward movement of the piston-shaped operating rod 2I during a circuit opening operation of the interrupter. When the arcing current falls to a relatively low value in the alternating current wave the arcs will return to the position at which they were initially drawn, that is, to a position directly across the center of the vent holes 2, 3, where the arcs 35, 36 are blasted by a cross-blast of fluid through the vents 2, 3 to the region external to the insulating casing I.

By the provision of such an interrupter, the arc is disturbed very little during high instantaneous values of arcing current, it being noted that interruption is not possible at times of high instantaneous values of arcing current. When, however, the arcing current falls to a relatively low instantaneous value and the arc is in a condition susceptible to interruption, the arc is returned to its cross-blast position at which time extinction is readily effected.

In the interrupter illustrated in Figs. 3 and 4 there is provided a cylindrically-shaped insulating casing 4!, in which is disposed a centrally positioned insulating operating rod 43 adapted for longitudinal movement within the insulating casing M and supporting two conducting bridging members 45 and 41. At the ends of the conducting bridging members 45 and 41 are movable main contacts 49, 53 and movable arcing contacts 5|, 55.

These movable contacts engage in the closed circuit position of the interrupter the respective stationary contacts 51, 6| and 59, 63. External line terminals 65 and 61 connect the breaker to an external circuit. In the closed circuit position of the interrupter the electrical circuit therethrough includes the external line terminal 65, the stationary main contact 51, the movable main contact 49, the conducting bridging member 45, a flexible conductor 69, the stationary main contact BI, the movable main contact 53, the conducting bridging member 41, flexible conductor 10 to lower external line terminal 61.

Encircling the insulating operating rod 43 are two compression springs H and 13. The compression springs H and 13 are disposed between washers 15 and 11, which are rigidly secured to the insulating operating rod 43, and the lower surfaces of the conducting bridging members 45 and 41. Pins 19 and BI limit the upward motion of the conducting bridging members 45 and 41 with respect to the insulating operating rod 43.

There is a permissible pivoting of the conducting bridging members 45 and 41 about the pins BI and 19 on the insulating operating rod 43. The purpose of the permissible pivoting motion of the conducting bridging members 45 and 41 netic fields surrounding the arcs 39, 49 and theabout the pins 8| and 19 with respect to the insulating operating rod 43 is to open the main contacts 51--49, |i|53, before the opening of the arcing contacts 59-5I, E3-55. By the placing of the main stationary contacts 51 and BI slightly above the respective stationary arcing contacts 59, 63, the upward and closing motion of the insulating rod 43 will result in closing the arcing contacts 63-55, 59-5I, before the closing of the main contacts 5149, 6|-53.

The pressure within the cylindrical insulating casing 4| is created by the arcs drawn therein. However, when low currents are being interrupted by the breaker the pressure provided by drawing series arcs in the liquid, in which the casing 4| is submerged, may not be sufficient to provide a sufficiently strong cross-blast of arc extinguishing fluid out through the vents 83, 85 provided in the walls of the casing 4I. Because of this I have provided a piston 81, which is adapted for longitudinal motion within a piston casing 89 upon being engaged by a pin 9| rigidly secured to the insulating operating rod 43.

Consequently, when the breaker is closed, the insulating operating rod 43 moves upward to cause engagement of the pin 9| with the piston 81 to move the piston 81 upward within the piston casing 89 against the bias of a compression spring 93, the latter disposed between the upper side of the piston 81 and the lower side of a cover plate 95. Closing movement of the breaker hence moves the piston 81 upwards to store energy in the compression spring 93. During a circuit opening operation when the current being interrupted is low the piston 81 will be forced downward by the compression spring 93 to increase the pressure of the liquid within the insulating casing 4!. If, on the other hand, the current being interrupted is high, the pressure within the insulating casing 4| created by the arcs may be sufficient to prevent downward motion of the piston 81. When, however, the pressure eventually subsides within the casing 4| after or during an interruption, the piston 81 will at this time move downward until the flange 91 engages the top surface of the top insulating plate 99 of the casing 4|. A scavenging of the arcing region and a building up of dielectric is thereby obtained.

When it is desired to open the interrupter, or when external overload conditions exist in the electrical circuit connected to the breaker, suitable actuating mechanism, not shown, provides a downward movement of the insulating operating rod 43. The initial downward movement of the insulating operating rod 43 produces a separation between the main contacts 5149, Iii-53, due to the initial pivoting motion of the conducting bridging members 45, 41 about the pivot pins BI, 19 being created by the disposition of the stationary main contacts 51, 6| at a higher level than the stationary arcing contacts 59, 63.

After the separation of the main contacts 51-49. 6|--53, the electrical circuit passing through the interrupter consists of the external line terminal 65, a stationary conductor I disposed adjacent the external surface of the easing 4| and connecting the external line terminal 65 with the stationary arcing contact 59, the arcing contact 59, movable arcing contact 5|, conducting bridging member 45, flexible conductor 69, stationary main contact 6|, a second stationary conductor I03 disposed adjacent the external surface of the casing 4| and connecting the stationary main contact 6| with the stationary areing contact 63, stationary arcing contact 63, movable arcing contact 55, conducting bridging member 41, flexible conductor 10 to external line terminal 61. At this point in the opening operation of the breaker no arcs have been formed.

Further downward motion of the insulating operating rod 43 separates the arcing contacts 59-5! 53-55. When this occurs two series arcs will be drawn respectively between stationary arcing contact 59, movable arcing contact 5|, stationary arcing contact 83, movable arcing contact 55. The electrical circuit now through the interrupter will be as follows: external line terminal 65, stationary conductor IOI, stationary arcing contact 59, are I01, movable arcing contact 5|, conducting bridging member 45, flexible conductor 69, stationary main contact 6|, sta tionary conductor I03, stationary arcing contact 63, are I09, movable arcing contact 55, conducting bridging member 41, flexible conductor 10, and external line terminal 61.

Referring particularly to Fig. 4 it will be observed that the stationary conductor IOI encircles the vent hole 85, and referring to the lower portion of Fig. 3 it will be apparent that the stationary conductor I53 also encircles the vent hole 83. The interaction during high instantaneous values of arcing current between the magnetic fields set up by the respective arcs I01, I09 and the portions III, II3 of stationary conductors I 0| and I03 is such to produce a lateral move ment of the arcs I01, I09, to one side of the respective vent holes 85, 83. Thus the pressure formed within the casing 4| by the piston 31 and by the arcs I01, I09 forces the liquid freely out through the vent holes 83, during high instantaneous values of current without substantially disturbing the continuity of the arcs, which at this time are displaced to one side of the vent holes 85, 83. When, however, the instantaneous value of arcing current decreases, the arcs I01, I09 are returned to the position where they were initially drawn, that is, directly in front of the vent holes 05, 83, to receive a transverse crossblast of arc extinguishing liquid through the arc stream and out of the vent holes 85, 83 to effect the extinction of the are.

In the embodiment of my invention shown in Figs. 5, 6 and 7 the reference numeral II5 designates an insulating casing suitably shaped so as to provid two flared vent holes H1, H9, across the inner ends of which are drawn two serially related arcs IiiI, I23 produced by downward movement of the insulating operating rod I25 and hence a moving of the conducting bridging member 21 away from the upper stationary contacts I29, I3I. An insulating barrier I32 is provided between the two arcs I2I, I23 for insulational purposes.

In this embodiment of my invention the magnetic fields surrounding the two arcs I2I, I23 interact to force the two arcs ILI, I23 to opposite sides of vent holes H1, H9 during relatively high instantaneous Values of arcing current. The displaced positions of the arcs I2I, I23 are indicated by reference numerals I22, I24. The pressure generated within the insulating casing II5 by the arcs I22, I24 during relatively high instantaneous values of current forces liquid within the casing II5 out through the vent holes In, I I9. During relatively high instantaneous values of arcing current the fluid is ejected through the casing |I5 through the vent holes H1, HQ without substantially disturbing the continuity of the two serially related arcs I 22, I 24 which at this decreases and the interaction between the two magnetic fields being correspondingly less, the arcs I22, I24 are permitted to return to the position where they were initially drawn, that is, directly in front of the vent holes I I1, I I9. At this position the two series arcs receive the direct effect of a cross-blast of liquid through the arc stream and out through the vent holes I I1, I I9 to extinguish the arcs.

In the embodiment of my invention shown in Figs. 8 and 9 there is provided a suitably shaped insulating casing I33 provided with a flared vent hole I35 and submerged in a suitable are extinguishing liquid. Across the inner edge of the flared vent hole I35 an arc, the position of which is indicated by the reference numeral I31, is drawn between the stationary contact I39 and the movable contact I4 I. Imbedded in the insulating casing I33 is a piece of magnetic material I43 positioned adjacent the arc I31. The are I31 will be affected by the presence of the piece of magnetic material I43 to cause the arc I31 to be attracted toward the piece of magnetic material I43 and hence to be drawn laterally to one side of the vent hole I35. Consequently, the pressure formed by the arc I31 within the casing I33 by the high instantaneous values of arcing current will cause the arc extinguishing fluid contained therein to be ejected through the vent hole I35 freely, the arc I31 at this time being displaced laterally to one side of the vent hole I35.

During relatively low instantaneous values of arcing current the attractive force exerted by the magnetic piece of material I43 will be less, and the arc will then be permitted to return to its former position directly in front of the vent hole I35, at which position it receives the full effect of the cross-blast of arc extinguishing fluid through the vent hole I35. This cross blast extinguishes the arc.

In the embodiment of my invention illustrated in Figs. 10 and 11, the reference numeral I41 designates an insulating casing in which an arc I49 is drawn between a stationary contact I5I and a movable contact I53 directly in front of a vent hole I55. Partially encircling the insulating casing I41 is a cylindrically-shaped sheet of magnetic material I51. The effect of the cylindrical sheet of magnetic material I51 on the arc I49 is to draw the arm I49 directly away (not to one side) of the vent hole I55 during relatively high values of instantaneous arcing current to a position indicated by reference numeral I58. A horizontal barrier of insulating material I59 is provided to prevent the arc I58 from being drawn too far away from the vent hole I55, since otherwise the attractive force between the cylindrically-shaped sheet of magnetic material I51 and the arc I58 would continue to increase as the arc I58 moved to the left, to result in the arc I58 being displaced too far away from vent hole I55.

During the displacement of the arc to its posi-- tion away from the vent hole I55, the liquid within the casing I41 has free access through the vent hole I55 without substantially disturbing the continuity of the arc I58 in its displaced position. At the same time the ionized gases are freely carried away without clogging the vent or interrupting structure. It is apparent that during relatively high instantaneous values of arcing current the arc will create pressure within the casing I41, this pressure forcing the ejection of fluid from the casing I41 out through the vent hole I55. When, however, the instantaneous value of arcing current decreases, the attractive force exerted by the cylindrically-shaped sheet of magnetic material I51 decreases, and the arc is permitted to return to its former position directly in front of the vent hole I55, at which position it receives a cross-blast of arc extinguishing liquid through the arc stream and out through the vent hole I55 to produce extinction of the are.

In the embodiment of my invention shown in Figs. 12, 13 and 14 there is provided an insulating cylindrical casing I6I longitudinally in which ,moves an insulating operating rod I63 carrying at its upper end a conducting bridging member I65, which connects in the closed. circuit position of the interrupter two stationary contacts I61, I69. A stationary conductor I1I extends upward from the stationary contact I59 and at the outer surface of the casing IIiI separates into two parallel branche I13, I15. The parallel branches I13, I15 connect at I11 to lead to an external line :terminal I19.

When the insulating operating rod I63 moves downward in a circuit interrupting operation of the interrupter, two serially related arcs I8I, I83- are drawn. Associated with each arc I8I, I83 is a magnetic field. Also associated with each of the two parallel conductors I13, I15 is a magnetic field. The strength of the magnetic field is a function of the instantaneous value of arcing current. The effect on the arc I83, which is initially drawn opposite vent hole I85, of the magnetic field associated with the arc I8I and the magnetic fields surrounding the stationary parallel conductors I13, I15 is such as to force the arc I83 directly back from the vent hole I (not to one side) during relatively high instantaneous values of arcing current to the position I84.

It is obvious that the arc I83 tends to be forced directly away from the arc I8I, but the effect of the magnetic fields set up about the two parallel branches I13, I15 is such as to overcome the repulsive effect of the arc I8I, and, in fact, to force the arc I83 in a direction towards the arc I8I and hence directly back from the vent hole I85 to position I84.

Consequently, as before, liquid within the insulating casing I6I, which is subjected to pressure by the two arcs I8I, I83, is forced out through the vent hole I85 during relatively high instantaneous values of arcing current, and in doing so substantially interferes very little with the displaced arc I84, When, however, the instantaneous value of arcing current diminishes, the strength of the respective magnetic fields will also diminish and the displaced arc I84 will re-- turn to the position at which it was initially drawn, that is, directly in front of the vent hole I85, at which position it will receive a strong cross-blast of liquid through the vent hole I85 to result in its extinguishment.

In the embodiment of my invention shown in Fig. 15 there is provided an insulating casing I81 in which is drawn an arc I89 between a stationary contact I9I and a movable contact I93. The are I89 is drawn directly across a vent hole I95.

The stationary contact I9I is connected by means of a conductor I91 to a series coil I99 so disposed that the magnetic field set up thereby is as indicated by the lines 2III. The effect of the magnetic field 20I set up by the series coil I99 upon the arc I89 during relatively high instantaneous values of arcing current is such as to move the arc I89 laterally to one side of the vent hole I95. Thus during relatively high instantaneous values of arcing current the arc extinguishing liquid disposed within the casing I8'I has free access to the vent hole I95 without substantially interfering with the continuity of the displaced arc I89. When, on the other hand, the value of instantaneous arcing current decreases the strength of the magnetic field set up by the series coil I99 correspondingly decreases, and the are I89 Will then be permitted to return to its former position directly in front of the vent hole I95, in which position it receives a direct cross-blast of are extinguishing liquid to effect the extinguishment thereof.

I do not wish to limit the scope of my invention to the utilization of an arc extinguishing liquid, it being readily apparent to one skilled in the art that my invention may be easily applied to gas blast breakers utilizing a gaseous arc extinguishing medium.

I have provided an interrupter in which the arc is drawn adjacent a vent, and the movement of the arc with respect to the vent depends upon the instantaneous value of arcing current. During high instantaneous values of arcing current the arc is moved away or to one side of the vent at which position it does not receive a direct cross-blast of arc extinguishing fluid. During this displaced position, however, it helps to generate pressure within the arc extinguishing chamber, this pressure being utilized during low values of instantaneous arcing current to help create a cross-blast through the are as is returns to its former position directly across the vent. Thus I move the arc to a position where it receives the full effect of the cross-blast of arc extinguishing fluid at a time when it is most susceptible to extinction, that is, at a time when the current through the arc stream is approaching a current zero. By moving the are away or to one side of the vent hole and thus disturbing it as little as possible during high instantaneous values of arcing current, the arc voltage is correspondingly kept low and the internal pressure within the arcing chamber is kept within reasonable limits.

Although in the description of each of the above embodiments of my invention the vent has been assumed to be the interrupting structure, naturally splitters or various kinds of arcing chutes which are Well known in the art could be used in conjunction with the vent hole to assist in the extinguishment of the are drawn adjacent thereto.

It will be observed that by moving the arc laterally to one side of the vent, or directly away from the vent, the relatively large quantity of gas which is formed during high instantaneous values of arcing current is not formed directly in front of the vent, as is the case with many commercial breakers now on the market. Consequently, the gas formed in a liquid breaker utilizing my invention during relatively high instantaneous values of arcing current does not clog, or raise the pressure at, the vent hole to interfere with the free venting of the liquid through the vent hole. Instead, being formed away from the vent hole, this relatively large quantity of gas is freely washed out of the breaker by the liquid flow. No clogging of the vent hole with products of decomposition or a raising of the pressure at the vent hole to prevent liquid flow, is the result of an applica tion of my invention to a liquid circuit interrupter.

Although I have shown and described specific embodiments of my invention, it is to be understood that the same were merely for the purpose of illustration and that changes and modifications may be made by those skilled in the art, without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a circuit interrupter, an arcing chamber, a passage leading from said chamber, means for establishing an are adjacent said passage, means for producing a flow of arc extinguishing fluid through said passage, and means for moving said arc away from said passage and laterally to one side thereof during relatively high instantaneous values of current.

2. In a circuit interrupter, an arcing chamber, a passage leading from said chamber, means for establishing an are adjacent said passage, means for producing a flow of arc extinguishing fluid through said passage, and means for disturbing the magnetic field surrounding said are to move said are away from said passage and laterally to one side thereof substantially only during relatively high instantaneous values of arcing current.

3. In an alternating current circuit interrupter, arc extinguishing fluid, means defining a substantially closed arcing chamber, a passageway leading from said chamber for the ejection of fluid from said chamber, means for causing a how of arc extinguishing fluid through said passageway, means for establishing an arc across said passageway within said chamber, and magnetic means for displacing said are away from said passageway and laterally to one side thereof only during relatively high instantaneous values of arcing current, the arrangement being such as to minimize the eiIect of said flow on said are during relatively high instantaneous values of arcing current.

4. In a circuit interrupter, a substantially closed arcing chamber having a vent, means for establishing an are within said chamber and adjacent the vent, means for extinguishing said are by a cross blast of arc extinguishing fluid through the vent, and magnetic means for minimizing said cross-blast only during relatively high instantaneous values of arcing current by moving the arc laterally to one side of the vent while permitting said arc to receive the full effect of said cross blast during relatively low instantaneous values of arcing current.

5. In a circuit interrupter of the cross-blast type, a substantially closed arcing chamber having a vent through which a cross-blast of arc extinguishing fluid may be established, means for establishing an are within said chamber and adjacent the vent, means for extinguishing said arc by a cross-blast of arc extinguishing fluid through the vent, and means disturbing the magnetic field surrounding said are to displace said arc laterally to one side of the vent substantially only during relatively high instantaneous values of arcing current, the effect of said displacement being to minimize the cross-blast during high instantaneous values of current and to effect an interruption of said are only during relatively low instantaneous values of current.

6. In a circuit interrupter, an arcing chamber, a passageway leading from said chamber, means for establishing an arc adjacent said passageway. means for producing a flow of arc extinguishing fluid through said passageway to help extinguish said arc, and magnetic means for varying said instantaneous value of arcing current by shifting the position of said arc laterally to one side of said passageway as a function of the instantaneous current through said arc.

7 In a circuit interrupter, a substantially closed chamber, a vent provided in the wall of said chamber, means for establishing two or more serially related arcs, at least one of said arcs being drawn adjacent said vent, means for producing a flow of arc extinguishing fluid through said vent to extinguish said are, the disposition of said two or more serially related arcs being in such proximity that said are is displaced away from said vent during relatively high instantaneous values of arcing current.

8. In a, circuit interrupter, means defining an arcing chamber, an orifice for said chamber, means for establishing two or more serially related arcs, at least one of said arcs being drawn adjacent said orifice, arc extinguishing fluid disposed within said chamber, means for creating pressure within said chamber to force fluid under pressure through said orifice and out of said chamber, the disposition of said two or more serially related arcs being such that said arc is displaced laterally to one side of said orifice during relatively high instantaneous values of arcing current.

9, In a circuit interrupter, a substantially closed arcing chamber, two or more vents provided in the wall of said chamber, means for producing a flow of arc extinguishing fluid under pressure through said vents and out of said chamber, means for establishing at least two serially related arcs Within said chamber, each of said arcs being drawn adjacent one of said vents, the disposition of said serially related arcs being such that each repels the other laterally to one side of the respective vents during relatively high instantaneous values of arcing current.

10. In a liquid alternating current circuit breaker, a substantially closed chamber, two vents in the walls of said chamber, means for establishing two serially related arcs directly across said vents, that is one are across each vent, said arcs generating pressure within said chamber to force liquid out of said chamber through said vents, said arcs being in such close proximity that each repels the other laterally to one side of the respective vents during relatively high instantaneous values of arcing current to permit a relatively free venting of liquid from said chamber, the two arcs returning to their initial positions in front of said vents to receive the full effect of the cross-blast of liquid through said vents during relatively low instantaneous values of arcing current.

11. In a circuit interrupter, an arcing chamber, an orifice in the wall of said chamber, means for establishing an are adjacent said orifice, means for producing a fiow of arc extinguishing fluid through said orifice to help extinguish said arc, and means comprising magnetic material for varying the amount of said fiow which acts on said are as a function of the instantaneous value of arcing current by moving the arc laterally to one side of the orifice only during relatively high instantaneous values of arcing current.

12. In a liquid break alternating current circuit interrupter, an arc extinguishing liquid, a substantially closed arcing chamber submerged in said liquid, a vent in the wall of said chamber, means for establishing an arc across said vent within said chamber, said arc producing pressure within said chamber to force liquid under pressure through said vent and out of said chamber, a sheet of magnetic material at least in part being disposed adjacent the wall of said chamber to attract said are away from said vent during relatively high instantaneous values of arcing current to permit a relatively free venting of liquid through said vent, and a barrier member of insulating material disposed so as to prevent said are moving too far away from said vent, the arrangement being such as to minimize the cross blast of liquid through said are during relatively high instantaneous values of arcing current and permitting the full effect of the cross-blast of liquid through said are during relatively low instantaneous values of arcing current.

13. In a circuit interrupter, one or more series conductors composed of solid conducting material, means for establishing at least two serially related arcs, means for producing a flow of arc extinguishing fluid adjacent one of said arcs, the disposition of the other of said arcs and of said series conductors being such as to vary said flow with respect to said first-mentioned are by shifting the position of said first-mentioned arc as a function of the instantaneous value of current through said first-mentioned arc.

14. In a circuit interrupter, a substantially closed chamber, a vent in the wall of said chamber, one or more series conductors composed of solid conducting material, means for establishing at least two serially related arcs, at least one of said arcs being established adjacent said vent, means for producing a flow of arc extinguishing fluid through said vent, the disposition of the one or more other of said arcs and of said series conductors being such as to move said firstmentioned are away from said vent during relatively high instantaneous values of arcing current.

15. In a liquid break alternating current circuit interrupter, a substantially closed arcing chamber, a suitable arc extinguishing liquid in which said chamber is submerged, a vent in the wall of said chamber, two serially related arcs being established within said chamber, one of said arcs being established within said chamber, one of said arcs being established across said vent, both of said arcs producing pressure within said chamber to force liquid out of said chamber through said vent, two parallel related series conductors straddling said vent externally of the wall of said chamber, said two serially related arcs and said vent being in substantial alignment, the arrangement being such that said first-mentioned arc is forced during relatively high instantaneous values of arcing current directly away from said vent toward said second-mentioned arc to permit a comparatively free venting of liquid through said vent, said first-mentioned are returning to its initial position across said vent to receive the full effect of the liquid flow through said vent during relatively low instantaneous values of arcing current.

16. In a circuit interrupter, an arc extinguishing fluid, a substantially closed arcing chamber, a vent in the wall of said chamber, means for creating a flow of said are extinguishing fluid through said vent and out of said chamber, means for establishing an are adjacent said vent within said chamber, a series conductor composed of solid conducting material, said series conductor being so disposed with respect to said arc that during relatively high instantaneous values of arcing current said are is moved laterally to one side of said event.

17. In a circuit interrupter, an arc extinguishing medium, a substantially closed arcing chamber, one or more vents disposed in the wall of said chamber, means for producing a flow of said are extinguishing medium through said one or more vents and out of said chamber, a stationary contact disposed adjacent each vent, a movable contact disposed adjacent each vent to establish an are adjacent each vent, one or more series conductors, said one or more series conductors being so disposed with respect to said arcs that said arcs are moved laterally to one side of said vents during relatively high instantaneous values of arcing current.

18. In a liquid break alternating current circuit interrupter, a substantially closed arcing chamber, arc extinguishing liquid disposed in said chamber, two vents disposed in the wall of said chamber, a stationary contact disposed adjacent each vent, a movable bridging member engaging said stationary contacts and cooperating therewith to draw two serially related arcs directly across said two vents, means for creating pressure within said chamber to force are extinguishing liquid through said two vents and out of said chamber, said bridging member comprising a series conductor so shaped and disposed as to move said two established arcs laterally to one side of their respective vents during relatively high instantaneous values of arcing current, the arrangement being such that during low instantaneous values of arcing current said two arcs return to their initial positions directly across said vents to receive substantially a cross-blast of arc extinguishing liquid through the arcs to eilect the extinction thereof.

19. In a circuit interrupter, a substantially closed arcing chamber, one or more main contacts, one or more arcing contacts, a vent in said chamber adjacent each of said arcing contacts, means for producing a flow of arc extinguishing fluid through said one or more vents and out of said chamber, means for opening said on or more main contacts before the opening of said one or more arcing contacts to establish an arc adjacent each vent, and one or more series conductors composed of solid conducting material connected in series circuit during at least part of the arcing period to move said arcs away from said vents during relatively high instantaneous values of arcing current.

20. In a liquid break alternating current circuit interrupter, a substantially closed cylindrically-shaped arcing chamber, arc extinguishing liquid disposed in said chamber, an operating rod movable longitudinally within said chamber, two pivotable bridging members, said rod carrying said two bridging members, two stationary main contacts, two stationary arcing contacts, two vents disposed in the wall of said chamber, each vent disposed adjacent a stationary arcing contact, means for producing a flow of said are extinguishing liquid through said two vents and out of said chamber, each bridging member carrying a movable main contact at one end and a movabl arcing contact at the other end, means for opening said arcing contacts after the opening of said main contacts to draw two serially related arcs across said two vents, two series conductors, each of said conductors connecting stationary main contact with a stationary arcing contact and curving around a vent in such a manner that the are drawn adjacent thereto is moved with respect to said vent during relatively high instantaneous values of arcing current.

21. In a liquid break alternating current circuit interrupter, a substantially closed arcing chamber, liquid disposed in said chamber, a vent disposed in the wall of said chamber, means for establishing an arc across said vent, a piece of magnetic material disposed adjacent said are to draw said are laterally to one side of said vent only during relatively high instantaneous values of arcing current, means for forcing said liquid under pressure through said vent and out of said chamber, said are remaining across said vent substantially only during relatively low instantaneous values of arcing current to receive the cross-blast of said liquid.

22. In a circuit interrupter, a substantially closed chamber, a vent in the wall of said chamber, means for establishing an arc adjacent said vent, arc extinguishing fluid, means for producing a flow of arc extinguishing fluid through said vent and out of said chamber, a series coil, said series coil being so disposed with respect to said are that said are is moved laterally to one side of said vent during relatively high instantaneous values of arcing current.

23. In a liquid break alternating current circuit interrupter, a substantially closed chamber, a vent in the Wall of said chamber, liquid disposed in said chamber, means for establishing an across said vent, said are creating pressure to force said liquid through said vent and out of said chamber, a series coil, the magnetic field created by said coil interacting with said are to move said are laterally to one side of said vent during relatively high instantaneous values of arcing current.

24. In a circuit interrupter, a substantially closed arcing chamber having a vent, means for establishing an are within said chamber and adjacent the vent, means for extinguishing said are by a cross-blast of arc-extinguishing fluid through the vent, and magnetic means comprising magnetic material for minimizing said crossblast only during relatively high instantaneous values of arcing current by moving the are laterally to one side of the vent while permitting said are to receive the full eilect of said cross-blast during relatively low instantaneous values of arcing current.

BENJAMIN P. BAKER. 

